Any beginner learning Linux command line tools would come across the cat command within the first week. Sooner or later, they'll come to know popular text processing tools like grep, head, tail, tr, sort, etc. If you were like me, you'd come across sed and awk, shudder at their complexity and prefer to use a scripting language like Perl and text editors like Vim instead (don't worry, I've already corrected that mistake).
Knowing power tools like grep, sed and awk can help solve most of your text processing needs. So, why would you want to learn text processing tools from the coreutils package? The biggest motivation would be faster execution since these tools are optimized for the use cases they solve. And there's always the advantage of not having to write code (and test that solution) if there's an existing tool to solve the problem.
This book will teach you more than twenty of such specialized text processing tools provided by the GNU coreutils package. Plenty of examples and exercises are provided to make it easier to understand a particular tool and its various features.
Github: https://github.com/learnbyexample/cli_text_processing_coreutils